ASTRO 1 Lecture 25: 25
Document Summary
Earth"s rotation: daylight covers half of earth, earth rotates from west to east, sky appears to move from east to west, sky is divided into 88 constellations. Earth"s orbit: the night sky changes during the year, the earth moves [360 degrees/12= 30 degrees] around the sun each month, the part of the star chart visible shifts by 2 hours of right ascension each month. Earth"s orbit de nes the ecliptic plane: ecliptic: apparent path of the sun around the celestial sphere, the 23. 5 degree tilt causes seasons. !1: the moons spins around exactly once per orbit, so we never see the far side of the moon. Ex: the far side of the moon is dark during the week before and the week after. Tilt of the moon"s orbit: we call the intersection of the two orbital planes the line of nodes, this 5 degree tilt makes eclipses rare, conditions required for eclipses.
